TCF7L2 and breast carcinoma: On the other hand, TCF7L2, ARRB1, DLL1, FZD7, HES1, and JAG1 transcript levels were significantly lower in breast cancer tissues than in normal samples (p < 0.0009, p = 0.0131, p =  < 0.0001, p =  < 0.0001, p = 0.0138, and p < 0.0001, respectively) (Fig. 5).